1IKITISH 1-oKKST TREES 33 



Ney again classifies them more broadly thus : 



Developing long stems All conifers except Cembran pine ; sessile 

 oak, chestnut, ash, maple, sycamore, birch, alder, poplars,horse-chestnut; 

 developing short stems English oak, beech, hornbeam ; limes, willows* 

 elms (op. cit. p. 60). 



\V lien the growings pace for each individual is limited, however, 

 these natural tendencies are checked ; the struggle upwards 

 for light and air induces growth in height, and counteracts 

 the propensity towards branching development. The less 

 the individual growing-space, and the more light-demanding 

 the species of tree, the greater the impulse towards growth 

 in height. In averagely dense forests of larch, Scots 

 pine, oak, birch, and aspen, the crown of foliage extends 

 a very little way down the stem, although in the insular 

 climate of Britain the Scots pine has a better crown than 

 on the hot, dry, sandy North-German plain, in spruce, 

 beech, and hornbeam it reaches down about one-third of the 

 bole, whilst in silver fir it often descends to about half w r ay 

 to the ground. Thus in forests of normal density supplies 

 of assimilated nourishment are available for the upper parts 

 of the bole in place of being dissipated over a large branch- 

 system, and are utilised in producing long, straight stems 

 approaching the cylindrical form, and thereby adding to 

 the value of the timber, both for technical purposes and 

 from a monetary point of view. 



The Age of the Crop is a factor of little moment in the 

 earlier stages of growth, as all species of trees, when grown 

 in forests of normal density, assume a more or less conical 

 or spindle-shaped crown until they outgrow the pole stage, 

 and become, with lessened growth in height, tree-forest, 

 when their individual natural tendencies begin to assert 

 their influence. Following their natural tendency, spruce, 

 silver fir, and larch continue to develop more vigorously 

 upwards than sidewards, thereby retaining their conical 



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